Thermal profile monitoring wafer and methods of monitoring temperature

ABSTRACT

Thermal monitors comprising a substrate with at least one camera position on a bottom surface thereof, a wireless communication controller and a battery. The camera has a field of view sufficient to produce an image of at least a portion of a wafer support, the image representative of the temperature within the field of view. Methods of using the thermal monitors are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/373,455, filed Aug. 11, 2016, the entire disclosure of which ishereby incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to apparatus and methods formeasuring and monitoring pedestal temperature. In particular,embodiments of the disclosure are directed to wafers for thermal profilemonitoring and methods of monitoring the thermal profile of a processingchamber.

BACKGROUND

Currently, TC wafers are used to measure the temperature of a pedestalin a processing chamber. The process of measuring temperature can betime consuming, resulting in long lead times to open the chamber,pump-down the chamber to processing conditions and perform thetemperature measurements. As throughput demands increase, the delaycaused by the temperature monitoring process becomes a larger issue.

There is a need for apparatus and methods for the determination ofpedestal temperatures that have a reduced delay in processing.

SUMMARY

One or more embodiments of the disclosure are directed to thermalmonitors comprising a substrate, a wireless communication controller anda battery. The substrate has a top surface and a bottom surface. Atleast one camera is positioned on the bottom surface of the substrate.The at least one camera has a field of view. The battery is connected tothe at least one camera and the wireless communication controller. Thethermal monitor has a total thickness sufficient to pass through a slitvalve of a processing chamber.

Additional embodiments of the disclosure are directed to thermalmonitors comprising a substrate, a plurality of high resolution thermalimaging cameras, a wireless communication controller, a battery and amicrocontroller. The substrate has a top surface and a bottom surface.The plurality of high resolution thermal imaging cameras is positionedat least on the bottom surface of the substrate. Each of the highresolution thermal imaging cameras produces a color gradient imagerepresentative of temperature variations. Each of the high resolutionthermal imaging cameras has a field of view and the fields of view ofthe high resolution thermal imaging cameras overlap to provide acomplete image. The wireless communication controller is configured tocommunicate through one or more of a wi-fi or Bluetooth standard. Thebattery is connected to the plurality of high resolution thermal imagingcameras and the wireless communication controller. The microcontrolleris connected to the wireless communication controller, the camera andthe battery. The microcontroller is configured to process data receivedfrom the plurality of high resolution thermal imaging cameras andtransmits the processed data through the wireless communicationcontroller. The thermal monitor has a total thickness sufficient to passthrough a slit valve of a processing chamber. The plurality of cameras,battery and wireless communication controller are operable attemperatures in the range of about 100° C. to about 500° C.

Further embodiments of the disclosure are directed to methods ofmonitoring temperature of a wafer support in a processing chamber. Themethod comprises positioning a thermal monitor on a plurality of liftpins. The thermal monitor has a substrate with at least one camera, awireless communication controller and a battery. The at least one camerais positioned on a bottom surface of the substrate and has a field ofview. The battery is connected to the at least one camera and thewireless communication controller. The plurality of lift pins supportthe thermal monitor so that there is a gap between the wafer support andthe bottom surface of the thermal monitor. The temperature of the wafersupport is measured using the at least one camera on the thermalmonitor.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 shows a perspective view of a thermal monitor in accordance withone or more embodiment of the disclosure;

FIG. 2 shows a cross-sectional view of a thermal monitor in accordancewith one or more embodiment of the disclosure;

FIG. 3 shows a cross-sectional view of a thermal monitor in accordancewith one or more embodiment of the disclosure; and

FIG. 4 shows a cross-sectional view of a processing chamber with athermal monitor in accordance with one or more embodiment of thedisclosure.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the disclosure, it isto be understood that the disclosure is not limited to the details ofconstruction or process steps set forth in the following description.The disclosure is capable of other embodiments and of being practiced orbeing carried out in various ways.

Embodiments of the disclosure provide a mock wafer of, for example,aluminum/glass fitted with one or more thermal imaging camera. Thecontrol electronics associated with the thermal imaging camera may alsobe included on the mock wafer. Some embodiments of the disclosureadvantageously provide temperature measurement devices that can be usedwith a standard process chamber.

The thermal imaging wafer can be loaded into the process chamber throughthe transfer chamber (load lock). Some embodiments of the disclosureadvantageously provide thermal imaging components to measure temperatureof the support pedestal which can fit within a standard load lock. Thethermal imaging wafer can collect thermal image data from the pedestal,process kit, target and showerhead of various semiconductor processingapparatus. Data can be transferred wirelessly to a control system. Thewireless transfer can occur by any suitable technique including, but notlimited to, Bluetooth® and wi-fi. In some embodiments, the thermalimaging wafer advantageously is sized to be included in a cassette withwafers for processing so that the thermal imaging wafer and thesubstrates to be processed are positioned in the system together,decreasing the impact on throughput.

FIGS. 1 and 2 show embodiments of the thermal monitor 100. The main bodyof the thermal monitor 100 comprises a substrate 110. As used in thismanner, a substrate 110 is a surface or component upon which othercomponents (e.g., cameras) are positioned. The substrate 110 can be madefrom any suitable material including, but not limited to, silicon,aluminum, quartz, glass and ceramic. While a round substrate 110 isshown in the Figures, those skilled in the art will understand that thisis merely one possible substrate shape and that other shapes are withinthe scope of the disclosure.

The substrate 110 includes a top surface 112, a bottom surface 114 and asidewall 116. In the embodiment shown in FIG. 1, the thermal monitor 100is inverted so that the bottom surface 114 of the substrate 110 isvisible. The substrate 110 has a thickness that is defined as thedistance between the top surface 112 and the bottom surface 114. If thetop surface 112 and the bottom surface 114 are substantially flat andparallel, the thickness of the substrate 110 is substantially the sameas the vertical dimension of the sidewall 116.

At least one camera 120 is positioned on the bottom surface 114 of thesubstrate 110. The embodiment shown in FIG. 1 has five cameras 120;however, those skilled in the art will understand that there can be anysuitable number of cameras. In some embodiments, there is one camera 120positioned on the bottom surface 114 of the substrate 110. In someembodiments, there are two, three, four, five, six, seven, eight, nine,10, 11, 12, 15, 20, 25 or more cameras 120 positioned on the bottomsurface 114 or other portions of the substrate 110. For example, asshown in FIG. 3, the substrate 110 has a plurality of cameras 120positioned on the bottom surface 114, top surface 112 and sidewall 116of the substrate 110. In some embodiments, there greater than or equalto 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20cameras 120 on the substrate 110.

The camera 120 can be any suitable camera capable of operating attemperatures greater than about 50° C. In some embodiments, the camera120 comprises a high resolution thermal imaging camera. In someembodiments, the camera 120 can obtain an image in the visible,ultraviolet (UV), near infrared (NIR), short-wavelength infrared (SWIR),mid-wavelength infrared (MWIR), long-wavelength infrared (LWIR) orfar-infrared (FIR). In some embodiments, the camera 120 is operable totake an image in the long-wavelength infrared (LWIR) region of theelectromagnetic spectrum. For example, the camera 120 may be operable tocapture light with wavelength in the range of about 8 to about 15 μm. Insome embodiments, the camera 120 is operable to capture light withwavelengths in the LWIR and FIR regions of the spectrum, for example,with wavelengths in the range of about 8 to about 1000 μm.

The camera 120 can be any suitable size depending on, for example, theamount of space available to insert the thermal monitor 100 into aprocessing chamber. The size of the camera 120 may also affect theresolution of the camera. A smaller camera has less physical spaceavailable for the imaging component. The term “high resolution” is usedto describe a camera with an imaging array of greater than or equal toabout 3000 pixels in an area of about 100 mm². In some embodiments, thecamera is a high resolution camera with greater than or equal to about3500, 4000 or 4500 pixels in an area of about 100 mm².

In some embodiments, the camera 120 has a thermal sensitivity less thanabout 200 mK. As used in this regard, the term “thermal sensitivity”means that the electronics of the camera 120 are capable of measuring atemperature difference as small as 200 milli-Kelvin. In someembodiments, the thermal sensitivity of the camera 120 is less than orequal to about 150 mK, 100 mK, 75 mK or 50 mK.

In some embodiments, the camera 120 produces a color gradient imagerepresentative of temperature variations. For example, relatively cooltemperature regions of the subject may be represented by blue whereasrelatively hot temperature regions of the subject may be represented byred, with the gradient of temperatures between the cool and hot regionsrepresented by the intermediate colors. The camera 120 may be capable ofproducing the color image or the color image may be generated by aseparate controller or processor that analyzes the image data capturedby the camera.

Each camera 120 has a field of view 122. The field of view 122 of eachof the cameras can be adjusted so that there is no overlap of theindividual fields of view 122 or so that there is overlap of the fieldsof view 122. Overlapping fields of view 122, as shown in FIG. 3, mayallow for a complete image of the wafer support 160 or processingchamber by combining (e.g., stitching) the separate images together toform a single image.

In the embodiment shown in FIG. 2, each camera 120 has a field of view122 that do not overlap. The cameras 120 shown have fields of view 122that align with each other so that the entire wafer support 160 isobserved by the plurality of cameras 120. In some embodiments, thefields of view 122 do not overlap and there is a gap between camerafields of view so that a partial view of the wafer support 160 is seen.

The fields of view 122 of the cameras 120 can be substantially the same(e.g., the same angle and relative direction) like that shown in FIG. 2.All of the cameras 120 shown have a field of view 122 directed downwardtoward the wafer support 160. In some embodiments, each of the pluralityof cameras 120 has a different field of view allowing for the monitoringof different directions from the substrate 110. For example, in theembodiment shown in FIG. 3, some of the cameras 120 have fields of view122 that are directed in different directions and with different anglesthan other cameras 120. This can be used to form a three-dimensionaltemperature map of the processing region of the processing chamber.

The thermal monitor 100 includes a wireless communication controller130. The wireless communication controller 130 can be connected to thecameras 120 and battery 140 through connections 135. As shown in FIGS. 1and 2, the connections 135 can be on the same side of the substrate 110or passing through the substrate 110. The order of connections shown inthe Figures is merely representative and should not be taken asindicating a specific combination and electrical circuit connections.

The wireless communication controller 130 can be any component that cantransmit data wirelessly from the inside of a processing chamber. Thewireless communication protocol can be any suitable type ofcommunication process. The communication process can use a communicationstandard, for example, wi-fi or Bluetooth.

The thermal monitor 100 also includes a battery 140 to power the camera120 and wireless communication controller 130. The battery 140 isconnected to the camera 120 and the wireless communication controller130 through connections 135. The battery 140 can be any suitable batterycapable of supplying sufficient power to operate the camera 120 andwireless communications controller 130 and any other components on thethermal monitor 100 that uses power (e.g., a microcontroller ormicroprocessor). Suitable batteries include, but are not limited to,cell-phone compatible power supplies, lithium ion batteries, lithiumpolymer batteries and alkaline batteries.

In some embodiments, as shown in FIG. 2, the thermal monitor 100 furthercomprises a microcontroller 150 connected to the wireless communicationcontroller 130, the camera 120 and the battery 140. As used in thismanner, a “microcontroller” includes firmware based microcontrollers andsoftware based microprocessors. The microcontroller 150 is any componentthat is capable of controlling the camera 120 and wireless communicationcontroller 130. The microcontroller 150 of some embodiments is capableof analyzing or processing data received from the camera(s) 120 andtransmit the processed data through the wireless communicationscontroller 130. In some embodiments, the wireless communicationscontroller 130 is an integral component of the microcontroller 150. Insome embodiments, the microcontroller 150 is configured to process datareceived from the at least one camera 120 and transmit the processeddata through the wireless communication controller 130. Themicrocontroller 150 of some embodiments is powered by the battery 140.In some embodiments, the microcontroller 150 has a separate power sourcefrom the battery 140.

Referring to FIG. 3, some embodiments of the disclosure are directed tomethods of monitoring temperature of a wafer support 160 in a processingchamber 200. The processing chamber 200 includes a chamber wall 202 witha bottom wall 203 and a sidewall 204. A lid 205 positioned on thechamber wall 202 encloses a processing volume 206.

A wafer support 160, also referred to as a substrate support, ispositioned within the processing volume 206 of the processing chamber200. The wafer support 160 includes a shaft 161 and at least one thermalelement 162. The shaft 161 passes through an opening 163 in the bottomwall 203 of the processing chamber 200 and is connected to a motor 164.The motor 164 can be capable of rotating the wafer support 160 andmoving the wafer support 160 in the z-axis. A bellows 166 forms a vacuumtight seal around the opening 163 in the bottom wall 203.

The processing chamber can also include a gas distribution assembly 170which can be positioned, as shown, adjacent the lid 205, or in otherlocations within the processing volume 206. The gas distributionassembly 170 is configured to flow at least one reactive or inert gasinto the processing volume 206. The gas distribution assembly 170 isgenerally spaced apart from the wafer support 160.

A thermal monitor 100 is positioned on a plurality of lift pins 180 inthe processing chamber 200. The number of lift pins 180 can be anysuitable number as is understood by those skilled in the art. Theembodiment of FIG. 4 shows two lift pins 180; however those skilled inthe art will understand that there is generally three or more lift pins180 to support the thermal monitor 100 or a wafer for processing.

The thermal monitor 100 is brought into the process volume 206 throughslit valve 186 by robot 185. The robot 185 and lift pins 180 can becontrolled by controller 220 to coordinate the movements of the liftpins 180 and the robot 185.

The robot 185 deposits the thermal monitor 100 on the lift pins so thatthere is a gap 182 between a top surface 168 of the wafer support 160and the bottom surface 114 of the thermal monitor 100. The gap 182 canbe any suitable size depending on, for example, the length of the liftpins 180 and the field of view 122 of the cameras 120. In someembodiments, the gap is greater than about 1 inch, 2 inches, 3 inches or4 inches.

The temperature of the wafer support 160 or the top surface 168 of thewafer support 160 can be measured using the camera(s) 120 of the thermalmonitor 100. In some embodiments, the camera 120 produces a colorgradient image representative of temperature variations on the wafersupport 160. The data received from the camera(s) 120 can becommunicated directly through the wireless communications controller 130to a system outside of the processing chamber 200 for furtherprocessing. In some embodiments, the data received from the camera(s)120 is processed by a microcontroller 150 and the processed data istransmitted through the wireless communications controller 130.

In some embodiments, the processed color gradient image is evaluated todetermine temperature variations of the wafer support 160. The localtemperature of the wafer support 160 can be modified based on theprocessed data to decrease or increase the temperature variations in thewafer support 160. For example, the controller 220 can evaluate thedata, or act on data evaluated by the microcontroller 150 and canincrease or decrease power to thermal elements 162 in the wafer support160. A multi-zonal thermal element system in the wafer support 160 canallow for pinpoint control of the temperature and thermal variations.

After measurement of the temperature and any data processing, thethermal monitor 100 is removed from the process volume 206 of theprocessing chamber 200. The thermal monitor 100 can be removed by therobot 185 through slit valve 186. In some embodiments, the lift pins 180do not lower the thermal monitor 100 to contact the wafer support 160.Stated differently, the lift pins 180 of some embodiments maintains adistance between the top surface 168 of the wafer support 160 and anycomponent on the thermal monitor 100.

The thickness of the thermal monitor 100 including all componentsthereon (e.g., battery, communications controller, cameras) issufficiently small to pass through a slit valve 186. In someembodiments, the thermal monitor 100 has a total thickness less than orequal to about 1 inch.

The thermal monitor 100, including any component positioned thereon(e.g., camera 120, wireless communications controller 130, battery 140and microcontroller 150) are operable at temperatures in the range ofabout 50° C. to about 500° C. In some embodiments, the thermal monitor100 and any components thereon, are operable at temperatures greaterthan or equal to about 100° C., 150° C., 200° C. or 250° C.

The process of measuring the temperature profile of the wafer supportcan be relatively quick. The entire process—loading the thermal monitorinto the processing chamber, measuring the temperature profile andremoving the thermal monitor—can be accomplished in less than about oneminute. In some embodiments, the entire process occurs in the range ofabout 5 to about 30 seconds or in the range of about 10 to about 20seconds.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A method of monitoring temperature of a wafersupport in a processing chamber, the method comprising: positioning athermal monitor on a plurality of lift pins, the thermal monitor havinga substrate with at least one camera, a wireless communicationcontroller and a battery, the at least one camera positioned on a bottomsurface of the substrate and having a field of view, the batteryconnected to the at least one camera and the wireless communicationcontroller, the plurality of lift pins supporting the thermal monitor sothat there is a gap between the wafer support and the bottom surface ofthe thermal monitor; and measuring the temperature of the wafer supportusing the at least one camera on the thermal monitor.
 2. The method ofclaim 1, wherein the at least one camera comprises a high resolutionthermal imaging camera.
 3. The method of claim 2, wherein the at leastone camera produces a color gradient image representative of temperaturevariations.
 4. The method of claim 3, further comprising processing thecolor gradient image from the at least one camera and transmitting theprocessed color gradient image using the wireless communicationcontroller.
 5. The method of claim 4, further comprising evaluating theprocessed color gradient image to determine temperature variations ofthe wafer support and a local temperature of the wafer support to modifythe temperature variations.
 6. The method of claim 5, wherein there area plurality of cameras on the substrate, each camera having a field ofview overlapping to provide a complete image of the wafer support. 7.The method of claim 4, wherein the wireless communication controller isconfigured to communicate through one or more of a wi-fi or Bluetoothstandard.
 8. The method of claim 7, wherein the thermal monitor furthercomprises a microcontroller configured to process data received from theat least one camera and transmit the processed data through the wirelesscommunication controller.